Add ide-assist: merge_attributes

crates/ide-assists/src/handlers/merge_attributes.rs

@@ -0,0 +1,229 @@
+use syntax::{
+    AstNode, NodeOrToken, SyntaxKind, SyntaxToken,
+    ast::{self, make},
+};
+
+use crate::{
+    AssistId,
+    assist_context::{AssistContext, Assists},
+};
+
+// Assist: merge_attributes
+//
+// Merge some attributes.
+//
+// ```
+// $0#[cfg(feature = "a")]
+// #[cfg(feature = "b")]
+// #[cfg(feature = "c")]$0
+// struct Foo;
+// ```
+// ->
+// ```
+// #[cfg(all(feature = "a", feature = "b", feature = "c"))]
+// struct Foo;
+// ```
+pub(crate) fn merge_attributes(acc: &mut Assists, ctx: &AssistContext<'_>) -> Option<()> {
+    let attr = ctx.find_node_at_offset::<ast::Attr>()?;
+    let name = attr.as_simple_call()?.0;
+    let extra_call = mergeable_attr(&name)?;
+    let attrs = attr
+        .syntax()
+        .siblings(syntax::Direction::Next)
+        .take_while(|node| node.text_range().start() < ctx.selection_trimmed().end())
+        .filter_map(ast::Attr::cast)
+        .collect::<Vec<_>>();
+    let is_outer = attr.excl_token().is_none();
+
+    if attrs.len() < 2
+        || attrs.iter().any(|attr| attr.as_simple_call().is_none_or(|it| it.0 != name))
+    {
+        return None;
+    }
+    let attr_tts =
+        attrs.iter().map(|attr| attr.meta()?.token_tree()).collect::<Option<Vec<_>>>()?;
+
+    let target = attr.syntax().text_range().cover(attrs.last()?.syntax().text_range());
+    acc.add(AssistId::refactor_rewrite("merge_attributes"), "Merge attributes", target, |builder| {
+        let name_path = make::ext::ident_path(&name);
+        let tts = attr_tts.iter().flat_map(|tt| comma_sep().chain(extract_tt_tts(tt))).skip(2);
+        let mut tt = make::token_tree(SyntaxKind::L_PAREN, tts);
+        if !extra_call.is_empty() {
+            tt = make::token_tree(
+                SyntaxKind::L_PAREN,
+                [NodeOrToken::Token(make::tokens::ident(extra_call)), NodeOrToken::Node(tt)],
+            );
+        }
+        let meta = make::meta_token_tree(name_path, tt);
+        let attr = if is_outer { make::attr_outer(meta) } else { make::attr_inner(meta) };
+        builder.replace(target, attr.to_string());
+    })
+}
+
+fn extract_tt_tts(
+    tt: &ast::TokenTree,
+) -> impl Iterator<Item = NodeOrToken<ast::TokenTree, SyntaxToken>> {
+    tt.token_trees_and_tokens().skip(1).take_while(|it| {
+        it.as_token().is_none_or(|token| {
+            !matches!(token.kind(), SyntaxKind::R_PAREN | SyntaxKind::R_CURLY | SyntaxKind::R_BRACK)
+        })
+    })
+}
+
+fn comma_sep() -> impl Iterator<Item = NodeOrToken<ast::TokenTree, SyntaxToken>> {
+    [make::token(SyntaxKind::COMMA), make::tokens::single_space()]
+        .into_iter()
+        .map(NodeOrToken::Token)
+}
+
+fn mergeable_attr(name: &str) -> Option<&'static str> {
+    match name {
+        "cfg" => Some("all"),
+        "derive" | "feature" | "allow" | "expect" | "deny" | "forbid" | "warn" => Some(""),
+        _ => None,
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::{check_assist, check_assist_not_applicable};
+
+    use super::*;
+
+    #[test]
+    fn test_merge_cfg_attributes() {
+        check_assist(
+            merge_attributes,
+            r#"
+$0#[cfg(feature = "a")]
+#[cfg(feature = "b")]$0
+struct Foo;
+            "#,
+            r#"
+#[cfg(all(feature = "a", feature = "b"))]
+struct Foo;
+            "#,
+        );
+
+        check_assist(
+            merge_attributes,
+            r#"
+$0#[cfg(feature = "a")]
+#[cfg(feature = "b")]
+#[cfg(feature = "c")]$0
+struct Foo;
+            "#,
+            r#"
+#[cfg(all(feature = "a", feature = "b", feature = "c"))]
+struct Foo;
+            "#,
+        );
+
+        check_assist(
+            merge_attributes,
+            r#"
+$0#[cfg(feature = "a")]
+#[cfg(feature = "b")]
+#[cfg(any(feature = "c", feature = "d"))]$0
+struct Foo;
+            "#,
+            r#"
+#[cfg(all(feature = "a", feature = "b", any(feature = "c", feature = "d")))]
+struct Foo;
+            "#,
+        );
+    }
+
+    #[test]
+    fn test_merge_derive_attributes() {
+        check_assist(
+            merge_attributes,
+            r#"
+$0#[derive(PartialEq)]
+#[derive(Clone)]$0
+struct Foo;
+            "#,
+            r#"
+#[derive(PartialEq, Clone)]
+struct Foo;
+            "#,
+        );
+    }
+
+    #[test]
+    fn test_merge_lint_attributes() {
+        check_assist(
+            merge_attributes,
+            r#"
+$0#[allow(unused)]
+#[allow(deprecated)]$0
+struct Foo;
+            "#,
+            r#"
+#[allow(unused, deprecated)]
+struct Foo;
+            "#,
+        );
+
+        check_assist(
+            merge_attributes,
+            r#"
+$0#[deny(unused)]
+#[deny(deprecated)]$0
+struct Foo;
+            "#,
+            r#"
+#[deny(unused, deprecated)]
+struct Foo;
+            "#,
+        );
+    }
+
+    #[test]
+    fn test_merge_outer_cfg_attributes() {
+        check_assist(
+            merge_attributes,
+            r#"
+$0#![cfg(feature = "a")]
+#![cfg(feature = "b")]
+#![cfg(feature = "c")]$0
+            "#,
+            r#"
+#![cfg(all(feature = "a", feature = "b", feature = "c"))]
+            "#,
+        );
+    }
+
+    #[test]
+    fn test_merge_attributes_not_applicable_other() {
+        check_assist_not_applicable(
+            merge_attributes,
+            r#"
+$0#![xxx(feature = "a")]
+#![xxx(feature = "c")]$0
+            "#,
+        );
+    }
+
+    #[test]
+    fn test_merge_attributes_not_applicable_single_attr() {
+        check_assist_not_applicable(
+            merge_attributes,
+            r#"
+$0#[cfg(feature = "a")]$0
+struct Foo;
+            "#,
+        );
+    }
+
+    #[test]
+    fn test_merge_attributes_not_applicable_different() {
+        check_assist_not_applicable(
+            merge_attributes,
+            r#"
+$0#![allow(unused)]
+#![deny(deprecated)]$0
+            "#,
+        );
+    }
+}

crates/ide-assists/src/lib.rs

@@ -183,6 +183,7 @@ mod handlers {
     mod introduce_named_lifetime;
     mod introduce_named_type_parameter;
     mod invert_if;
+    mod merge_attributes;
     mod merge_imports;
     mod merge_match_arms;
     mod merge_nested_if;
@@ -319,6 +320,7 @@ mod handlers {
             introduce_named_lifetime::introduce_named_lifetime,
             introduce_named_type_parameter::introduce_named_type_parameter,
             invert_if::invert_if,
+            merge_attributes::merge_attributes,
             merge_imports::merge_imports,
             merge_match_arms::merge_match_arms,
             merge_nested_if::merge_nested_if,

crates/ide-assists/src/tests/generated.rs

@@ -2436,6 +2436,23 @@ fn main() {
     )
 }
 
+#[test]
+fn doctest_merge_attributes() {
+    check_doc_test(
+        "merge_attributes",
+        r#####"
+$0#[cfg(feature = "a")]
+#[cfg(feature = "b")]
+#[cfg(feature = "c")]$0
+struct Foo;
+"#####,
+        r#####"
+#[cfg(all(feature = "a", feature = "b", feature = "c"))]
+struct Foo;
+"#####,
+    )
+}
+
 #[test]
 fn doctest_merge_imports() {
     check_doc_test(